Respiratory syncytial virus (RSV) is a leading cause for bronchiolitis and severe respiratory disease in infants, young children, immune-compromised and elderly populations worldwide. Natural RSV infection in young children does not elicit long-lasting immunity and individuals remain susceptible to repeated RSV infections throughout life. A formalin-inactivated RSV (FI-RSV) vaccine, tested in infants a half century ago, resulted in enhanced morbidity and two deaths after a subsequent exposure to a natural RSV infection. The infants and children that received the FI-RSV vaccine exhibited a lower level of neutralizing antibodies following a natural infection (Yang and Varga, 2014).
While much efforts and resources have been devoted to the development of a safe and effective RSV vaccine, there is no licensed RSV vaccine available so far. The researches carried out so far demonstrated that it is a daunting challenge for developing a safe and effective RSV vaccine.
Therefore, there is an imperative need to explore new ways to develop a safe and effective vaccine against RSV.